Finding cash to fund TV commercials is "the only thing that matters in American politics now", former US Vice-President Al Gore has said.

"The person who has the most money to run the most ads usually wins," he told the Edinburgh TV Festival.

It was "astonishing" that the average American devoted nearly five hours a day to TV viewing, he added.

And Mr Gore asserted the internet was making TV more accessible and letting people join a "multi-way conversation".

He called this an important move because people could find and distribute information, and then watch as it was judged by others in terms of quality.

Amateur film-makers

Mr Gore has become an environmental campaigner, and is in Edinburgh partly to promote his film and book, An Inconvenient Truth, which address the climate change crisis.

He is also president of CurrentTV, a channel that champions the work of "amateur" programme-makers who may be making names for themselves online.

In my country, the average American watches television for four hours and 39 minutes a day. Astonishing, really

Al Gore

About 30% of his station's output originates in this way but that this was likely to increase in the future, he added.

On the subject of the expenditure of political parties, Mr Gore, a Democrat, said: "Two days ago, I was at an event helping to raise money for a candidate of my political party, running for governor in one of our most populous states.

"I asked the question of him: 'What percentage of your campaign budget, between now and election day in November, will be spent on television commercials?'

"The answer was 80%," he told an audience of several hundred media industry figures on the final day of the festival.

"In my country, the average American watches television for four hours and 39 minutes a day. Astonishing, really.